The present invention concerns deployment mechanisms for use on aircraft wings. More particularly, but not exclusively, this invention concerns deployment mechanisms for deploying an auxiliary wing surface device from an aircraft wing body. The invention also concerns aircraft wings, an aircraft and methods of operating aircraft.
Modern aircraft wings are designed to maximise the angle of attack during take-off and landing operations. This often involves the wing having high-lift devices, with air-profiled surfaces, that can be extended and retracted along a predefined path in relation to the main wing body. These devices can be extended from the leading edge or from the trailing edge of the main wing body.
Prior art methods of deploying the high-lift devices generally comprise a power drive unit, gears, rotary (or possibly linear) actuators, a drive shaft, rotation control sensors and a set of linkages. This makes them bulky, heavy and complicated. An alternative method that has been used to deploy a trailing edge flap comprises a flap track beam with a mechanical gear and ball screw spindle attached to it. A ball nut is attached to the flap using a gimble arrangement. Movement of the nut along the stationary spindle deploys the flap and the gimble arrangement allows the flap to rotate into the desired orientation.
There are three main types of high-lift device; slats, drooped noses and Krueger flaps. Krueger flaps are generally used on a leading edge of a main wing body which is designed to maximise laminar flow along the upper wing surface. A typical Krueger flap, in its retracted position, forms at least part of the leading edge of the main wing body. This means that the profile of the Krueger flap is blended with the lower profile of the leading edge. This means that laminar flow when the flap is stowed (i.e. during cruise) is not disturbed.
However, as Krueger flaps are often used with narrow profiled wings designed for laminar flow, and because the Krueger flap stows within the profile of the wing, the deployment mechanisms needed to extend and retract the Krueger flaps need to be small. A small size of deployment mechanism is also needed so that a minimum required clearance to other systems in the wing (for example in the leading edge of the wing) and to other structures (e.g. a fuel tank) in the wing can be achieved.
The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved deployment mechanism, especially for a Krueger flap.